Enhancement Of Tensile Strength Research Articles

Promoting nanoprecipitates via prefabricated defects to pin dislocations and grain boundaries for trading off high-strength and low-thermal-expansion of invar alloys

Invar alloys that combine high strength with a low coefficient of thermal expansion (CTE) are urgently required for industrial applications. Based on the lower coarsening rate during aging and the CTE values of carbonitrides, a novel strategy is proposed to prepare carbonitrides by reducing carbon and increasing nitrogen to design high-strength and low-thermal-expansion invar alloys. The V(C, N) nanoprecipitate was introduced into the invar alloy, and its effects on the microstructure, thermal expansion behavior, and mechanical properties were investigated. The direct-aged alloy exhibited an enhanced tensile strength of 525 MPa and a ductility of 47.6%. The cold-deformation aging alloy achieved an enhanced tensile strength of 815 MPa while retaining 7.4% ductility and a low CTE value of 1.23×10−6 /°C. The V(C, N) nanoprecipitates effectively immobilized dislocations and grain boundaries, leading to a high dislocation density and small grain size in the alloy. The contributions of each strengthening mechanism were calculated, and the precipitation and dislocation strengthening were found to be the main mechanisms of strength enhancement. These results provide a novel approach for preparing high-strength and low-CTE invar alloys.

A 4D-Printable Photocurable Resin Derived from Waste Cooking Oil with Enhanced Tensile Strength.

In pursuit of enhancing the mechanical properties, especially the tensile strength, of 4D-printable consumables derived from waste cooking oil (WCO), we initiated the production of acrylate-modified WCO, which encompasses epoxy waste oil methacrylate (EWOMA) and epoxy waste oil acrylate (EWOA). Subsequently, a series of WCO-based 4D-printable photocurable resins were obtained by introducing a suitable diacrylate molecule as the second monomer, coupled with a composite photoinitiator system comprising Irgacure 819 and p-dimethylaminobenzaldehyde (DMAB). These materials were amenable to molding using an LCD light-curing 3D printer. Our findings underscored the pivotal role of triethylene glycol dimethacrylate (TEGDMA) among the array of diacrylate molecules in enhancing the mechanical properties of WCO-based 4D-printable resins. Notably, the 4D-printable material, composed of EWOA and TEGDMA in an equal mass ratio, exhibited nice mechanical strength comparable to that of mainstream petroleum-based 4D-printable materials, boasting a tensile strength of 9.17 MPa and an elongation at break of 15.39%. These figures significantly outperformed the mechanical characteristics of pure EWOA or TEGDMA resins. Furthermore, the EWOA-TEGDMA resin demonstrated impressive thermally induced shape memory performance, enabling deformation and recovery at room temperature and retaining its shape at -60 °C. This resin also demonstrated favorable biodegradability, with an 8.34% weight loss after 45 days of soil degradation. As a result, this 4D-printable photocurable resin derived from WCO holds immense potential for the creation of a wide spectrum of high-performance intelligent devices, brackets, mold, folding structures, and personalized products.

Influence of Bismuth Addition on the Physical and Mechanical Properties of Low Silver/Lead-Free Sn-Ag-Cu Solder

The Sn–Ag–Cu (SAC) solders with low Ag content have been identified as promising candidates to replace the traditional Sn–Pb solder for flip-chip interconnects. This study examines the impact of incorporating Bi element on the microstructure, thermal behavior, and mechanical performance of low-silver-content Sn-1.5Ag-0.7Cu (SAC157) solder alloy. Besides using the conventional cross-sectioned microstructure image, X-ray diffraction (XRD), differential scanning calorimetry (DSC) and tensile stress- strain techniques were used to investigate the microstructure, thermal and mechanical properties after the addition of Bi, respectively. The results demonstrate that adding of Bi could refine the microstructure, optimize the thermal properties, and improve the tensile strength. Meanwhile, the ductility of the solder alloys reduced evidently in comparison to the Sn-1.5Ag-0.7Cu solder. From the microstructural analysis, 0.5wt% Bi addition to SAC157 significantly enhanced the solid solution effect of Bi and refined β-Sn dendrite, as well as extended the eutectic area. Moreover, as the Bi addition increases to 5wt%, finely dispersed bismuth precipitates within the β-Sn matrix, along with an enlarged eutectic area, lead to a remarkable enhancement in both ultimate tensile strength and yield strength. The electrical resistivity was characterized by the four-point probe technique. The results show that the electrical resistivity of Bi-modified SAC157 solder alloy decrease from 13.9 to 9.8 μΩ cm with the addition of 5wt.% Bi. These improvements can be attributed to the solid-solution and precipitation strengthening effects induced by the presence of bismuth. The results confirmed that the developed material is applicable as a potential high strength solder material in the context of advanced interconnecting applications.

Effect of Soybean Oil on the Improvement of the Functionality of Edible Membrane-Type Food Packaging Films Based on Caseinate–Сarboxymethyl Chitosan Compositions

Edible film biopolymers are gaining attention to tackle problems of plastic waste and food safety to alleviate environmental problems associated with plastic products in food packaging. In this study, caseinate–carboxymethyl chitosan (CA–CMCH) composite films were made with the incorporation of soybean oil (SO) using a casting technique. The influence of different soybean oil concentrations at 0, 0.5, and 1% (w/w) on physical, mechanical, barrier, and surface characteristics of films composed of caseinate–carboxymethyl chitosan (CA–CMCH) was evaluated. The brightest film (L* value of 95.95 ± 0.30) was obtained with the edible film made from the control group of samples with sodium caseinate (NaCA-100; 100% NaCA). The results also indicated that samples with 1% SO in NaCA-75 and CaCA-75 had lower water vapor permeability (WVP), while those with NaCA-50 and CaCA-50 showed higher values of WVP. For mechanical properties, this study found that incorporating soybean oil into the caseinate–carboxymethyl (CA–CMCH) composite films led to an enhancement of both tensile strength and elongation at break. The morphological structures, determined using SEM, of control and composite films showed compact and homogenous surfaces. Overall, the addition of soybean oil contributed to the improvement of the functional properties of the edible films, offering potential solutions to the environmental issues associated with plastic packaging and enhancing the safety and performance of food packaging.

Achieving enhanced strength retention at elevated temperatures in ultrafine-fibrous interconnected Al–Ce–Ni eutectic alloy solidified under super-gravity field

Super-gravity field was reported to strongly intensify the buoyancy-driven flow of liquid during solidification, affecting the solute convection and morphology of eutectic structure in binary alloys. In ternary eutectic alloys, certain two-phase regions with a coarse structure can usually be detected concurrently along with three-phase eutectics, leading to the formation of heterogeneous structure with limited ductility. Currently, Al–Ce–Ni ternary eutectic alloy was chosen as a modal system, which was reported for the first time to be solidified under super-gravity field with high volume fraction of three-phase eutectics. Meanwhile, the formation of ultrafine-fibrous interconnected Al11Ce3–Al3Ni eutectic clusters with more “chains” and higher spatial connectivity was detected mainly due to the relatively higher nucleation rate. The high volume fraction and refinement of interconnected Al11Ce3–Al3Ni eutectic clusters with excellent thermal stability could contribute to enhancement of ductility and tensile strength at elevated-temperature. Interestingly, the strength retention at 300 °C and 400 °C were able to reach up to ∼68.1 % and ∼33.2 %, respectively.

Bromine-enhanced polarization for strengthening ultra-thin copper foil in lithium-ion battery

Reducing the weight of the negative current collector is an effective strategy for lightweighting vehicle batteries. Herein, thin copper foil with high tensile strength was prepared through electrodeposition in Br−-based aqueous solution. The synergistic effect of additive Br−, polyethylene glycol (PEG), Bis-(sodium sulfopropyl)-disulfide (SPS) on the microstructure and tensile strength of the copper foils have been systematically explored. It was found that the addition of Br− modifies the microstructure of copper via grain refinement, thereby enhancing the mechanical properties of copper foil. The obtained copper foil reaches an enhanced tensile strength of 469.8 N/mm2 and an elongation of 2.2%. The results of electrochemical measurements confirm that Br− enhances electrochemical polarization of PEG and attenuates the acceleration of SPS. The improved mechanical properties of copper foils are attributed to the closer proximity and stronger adsorption energy between Br− and Cu atoms, which results in a synergy of grain refinement and nanotwinned grains associated with increased dislocation density as well as dislocations entangled around nanotwin GBs.

Enhancing strength–ductility synergy of AlNp/Al composite by regulating heterostructure of matrix grain and particle distribution

Three heterostructured AlNp/Al composites with different microstructure configurations were fabricated by liquid–solid reaction combined with subsequent thermal-mechanical treatment to obtain a superior strength and ductility combination. The effects of the microstructure configuration including the AlN particle distribution and matrix grain structure on the tensile strength and ductility were studied in detail. The results show that the simultaneous enhancement of tensile strength and ductility can be achieved. The Uniformed-AlNp/Al composite with relatively dispersed particles exhibits a superior ultimate tensile strength of ~387 MPa with an elongation to failure of ~9.1%. It shows an outstanding specific tensile strength and elongation combination compared with other reported particle reinforced aluminum matrix composites. Furthermore, the hetero-deformation induced (HDI) stress has been calculated and is shown to increase significantly in the Uniformed-AlNp/Al composite. It is revealed that the HDI stress plays a crucial role in the significant enhancement of strength and ductility for the AlNp/Al composite.

Effect of steel fiber shape and content on printability, microstructure and mechanical properties of 3D printable high strength cementitious materials

This study investigates the effects of steel fiber shape (straight and hooked-end) and content (0, 0.5, 1.0, and 1.5 vol%) on rheological properties, printability, mechanical performance and microstructure of 3D printable steel fiber reinforced high strength concrete (3DP-SFHSC). The results indicate that the increase of fiber content improves the mechanical behaviors of 3DP-SFHSC, but the extrudability suffers from reduction when the fiber content exceeded 1.0 vol% due to the significant increase in yield stress. The addition of 1.5 vol% hooked-end fibers enhances the compressive strength of 3DP-SFHSC by 8%, 25.7%, and 40.4% in the X, Y, and Z directions, respectively. Additionally, it also improves the tensile strength in the X direction by 37.67%. The printed specimens exhibit weaker mechanical properties compared to the cast specimens. On the one hand, the lower fiber-matrix compactness resulting from the absence of vibration during printing leads to increased porosity and weak bonding between the steel fibers and matrix. On the other hand, the inconsistent movement between fibers and mortar matrix during extrusion process may also cause the formation of gaps around fibers. Straight fibers show pronounced enhancements in buildability, compressive strength and tensile strength compared to hooked-end fibers at the same fiber volume fraction. Straight fibers align easily during the extrusion process, contributing to a matrix with lower porosity and smaller average pore size.

Synthesis of castor oil/PEG as textile softener

New castor oil/polyethylene glycol (CAO/PEG) hybrids were synthesized by reacting of CAO with PEG 300, 600, 1000, 2000 or 4000, in presence of ammonium per sulfate (APS) as an initiator. The optimum conditions to synthesis such hybrids are: PEG/CAO weight ratio, 35%; APS/PEG weight ratio, 15%; reaction temperature, 80 °C; and reaction time, 60 min. Only the hybrids based on PEG 1000 and 2000 formed oil in water stable emulsions. Treating cotton fabric samples with easy care finishing formulation containing 40 g/L of the synthesized hybrids emulsions results in an enhancement in softness, tensile strength, whiteness index, and stiffness along with a reduction in nitrogen content, wrinkle recovery angle, and wettability properties of treated fabric, compared to that sample finished in absence of that emulsions. The chemical structure of the synthesized CAO/PEG1000 hybrid was confirmed via the FTIR and 1HNMRanalysis whereas the TEM analysis showed that the particles size of that hybrid emulsion is in the range of 27–105 nm. Moreover, such hybrid emulsion treated fabric surface was characterized via SEM and EDX analysis. Furthermore, treating dyed samples with the nominated hybrid emulsion improves the color strength of that samples but keeps the washing fastness, wet rubbing fastness as well as alkaline perspiration fastness of the dyed/finished samples unchanged. The wet rubbing fastness and alkaline perspiration fastness of all the dyed/finished samples were enhanced while the light fastness of such samples decreased.

Novel short Agave americana based biocomposite and nanobiocomposites for automotive applications

Short fibers of Agave Americana (AA) was extracted from its plant leaf, was chemically treated with Ac2O, HCOOH, H2O2, KMnO4 and NaOH, and then characterized by Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), thermo-gravimetric/differential thermo-gravimetric (TGA/DTG), and field emission-scanning electron microscopy (FE-SEM). PVA stabilized copper nanoparticles from chemical reduction method was characterized using field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDAX), powder X-ray diffraction (PXRD), Dynamic light scattering analysis (DLS), UV–visible absorption spectroscopy, Fourier Transform infrared (FT-IR) spectroscopy and Thermogravimetric analysis/differential thermogravimetry (TGA/DTG). Bio-composites (AA + Polyester Resin (PE) and hybrid nano bio-composites (AA + Polyester Resin (PE) + Cu) were prepared from the untreated and treated AA fibers and further characterized. The synergistic effect of chemical treatment on morphological (SEM), thermal (TGA/DTG), mechanical properties (flexural, tensile, impact and compressive strength) followed by % water absorption were examined. The average surface roughness values (Ra) of chemical treated fiber was identified to be in decreasing manner along with compression strength of biocomposite in the order of untreated (10.74 μm, 44.01 MPa) > NaOH (8.55 μm, 45.07 MPa) > HCOOH (3.49 μm, 24.10 MPa) Ac2O (3.24 μm, 22.10 MPa) > H2O2 (2.51um, 17.9 MPa) > KMnO4 (1.52 μm, 15.1 MPa) treated fibers. Subsequently, the addition of 2s@PVA led to reverse the order namely, the compressive strength of the bionanocomposites were Untreated (10.74 μm, 9.0 MPa) < NaOH (8.55 μm, 0.1 MPa) < HCOOH (3.49 μm, 3.6 MPa) < Ac2O (3.24 μm, 7.6 MPa) < H2O2 (2.51um, 13.3 MPa) < KMnO4 (1.52 μm, 44.1 MPa) treated fibers. Similarly, the biocomposite where the fibres were treated with NaOH, HCOOH were more rough and had, good interconnection between fiber/PE matrix along with enhanced mechanical properties. On addition of nanobiocomposite, only KMnO4 treated fiber composite possed significant mechanical properties. Therefore, mixing CuNPs@PVA with KMnO4 treated fibers led to significant boost to the mechanical properties and minimised the % water absorption properties when compared to the untreated AA/PE biocomposites. The KMnO4 treatment of the AA fiber and addition of copper nanoparticles caused the enhancement of thermal properties, tensile strength and flexural strength. But, these nanobiocomposites were observed to have low impact strength; while, H2O2 treated nanobiocomposites had highest impact strength. The chemical treatment of the AA fiber with NaOH, Ac2O and KMnO4 developed the water resistance of the respective biocomposites. All the nanobiocomposites with chemically treated AA fibers (except Ac2O) were found to have high water resistance. So, they can be used in automotive industry for non-structural applications.

Mechanically Controlled Enzymatic Polymerization and Remodeling.

In nature, proteins possess the remarkable ability to sense and respond to mechanical forces, thereby triggering various biological events, such as bone remodeling and muscle regeneration. However, in synthetic systems, harnessing the mechanical force to induce material growth still remains a challenge. In this study, we aimed to utilize low-frequency ultrasound (US) to activate horseradish peroxidase (HRP) and catalyze free radical polymerization. Our findings demonstrate the efficacy of this mechano-enzymatic chemistry in rapidly remodeling the properties of materials through cross-linking polymerization and surface coating. The resulting samples exhibited a significant enhancement in tensile strength, elongation, and Young's modulus. Moreover, the hydrophobicity of the surface could be completely switched within just 30 min of US treatment. This work presents a novel approach for incorporating mechanical sensing and rapid remodeling capabilities into materials.

Fast-setting multi-stimuli responsive silk hydrogels tailored with dual network interface

Silk fibroin, a naturally occurring and versatile polymer with broad range of material forms and applications, presents numerous advantages. Notably, hydrogels are noteworthy among these advantages due to their inherent hydrophilicity, biocompatibility, and flexibility. Nevertheless, their practical utility has been hindered by intricate preparation procedures and limited mechanical strength. In this investigation, we introduce a straightforward and cost-effective method for producing a novel silk hydrogel. Subsequent to the hydrogel synthesis, an ethanol treatment was employed to induce the preferential formation of β-sheet conformations. The developed system exhibits rapid gelation (gelation time: 3 min) and non-swelling behavior (swelling ratio = 0.47). This suggests its potential suitability for biomedical devices without imposing strain on adjacent tissues. Conformational rearrangement of polymeric chains induced by ethanol treatment contributed to heightened material crystallinity, resulting in a remarkable 55.9% increase in Young's modulus and a substantial 91.2% enhancement in ultimate tensile strength for the ethanol-treated hydrogels (SF/AG/Gly/Eth) when compared to their non-ethanol-treated counterparts (SF/AG/Gly). Additionally, in-situ biodegradation studies on silk hydrogels confirmed the material's degradability, with a notable 94.75% weight loss within 3 days, following pseudo-second-order kinetics (R2 = 0.991). This degradation is attributed to action of proteolytic enzymes on the amino acid units of silk fibroin, alleviating concerns regarding waste generation. Moreover, these pH and water-responsive hydrogels can be harnessed in the fabrication of intelligent biomedical devices. Further, drug release studies on silk hydrogels showed that both ethanol-treated and non-treated samples displayed sustained drug release following the Korsmeyer−Peppas model, with an entrapment efficiency of 65.6% and 48.2%, respectively.

Ultraviolet shielding composites of different cellulose/aramid nanofibers

In order to improve the UV shielding properties of cellulose nanofibers (CNF), aramid nanofibers (ANF) are used as additives. For composite preparation, three distinct CNFs are used in this work: ionic liquid mediated hydrolyzed (ILCNF), high-speed mechanically sheared (MCNF), and TEMPO-mediated oxidized (TCNF) to identify the effect of surface functionality and morphology on the composite properties. The performance of the prepared composites is compared by evaluating their UV shielding and mechanical properties. Due to the maximum (7.9 nm) and minimum (3.5 nm) average fibre diameters, respectively, pristine MCNF had minimum transparency and TCNF had maximum transparency. 5 wt% ANF - TCNF composite had maximum UV-250 and UV-300 nm shielding ratios of 74.6 and 93.7%, respectively. For the same composite, an enhancement in tensile strength of 117% is also noted. According to these findings, TCNF composite with 5% ANF has excellent UV shielding, superior transparency in the visible light region, and outstanding mechanical strength.

Pencil‐Shaped Necking of Thick Al Whisker Grown by Stress‐Induced Migration and Enhancement of Tensile Strength

This study aims to characterize the mechanical response of thick Al whiskers under tension. Wire‐shaped whiskers are fabricated by stress‐induced migration using an original sample structure. Straight and single‐crystal whiskers are suspended between a W probe tip attached to a micromanipulator and an atomic force microscope tip attached to a nanostage using electron beam irradiation hardening glue. Tensile tests are conducted by pulling the probe tip. A tensile strength of 1 GPa is obtained for a whisker with a diameter of 500 nm. Observations using a high‐voltage electron microscope show that the whisker is deformed by pencil‐shaped sharp necking with signs of recrystallization at the tip, which displays a novel mechanical response of Al whiskers. The obtained tensile strength is more than twice that of whiskers with similar diameters reported in the literature, indicating that the tensile strength of not only thin, but also thick whiskers can be enhanced by activating a different mode of deformation.

Fabrication and characterization of chitosan/anthocyanin intelligent packaging film fortified by cellulose nanocrystal for shrimp preservation and visual freshness monitoring

In this study, a multi-functional packaging film was fabricated, utilizing the natural polysaccharide chitosan (CS) as the base material, integrating natural blueberry anthocyanin (AN) as pH-responsive indicator, and reinforced with cellulose nanocrystals (CNCs). The implications of addition levels of CNCs on the characteristics of the films were systematically investigated, resulting in that CS-AN-CNCs 9 % film exhibited optimal performance. Specifically, the film showed a substantial enhancement in maximum tensile strength from 15 MPa to 35 MPa; On the other hand, the swelling degree properties, the oxygen permeability and water vapor permeability decreased from 159.2 % to 92.0 %, from 51.7 g/(m2d) to 12.2 g/(m2d), from 31.6 × 10−12 g/(m·s·Pa) to 1.6 × 10−12 g/(m·s·Pa), respectively. Moreover, the CS-AN-CNCs 9 % film exhibited antioxidant, antibacterial, coupled with a color metrically responsive to pH variations, displaying great potential in indicating the shrimp freshness and delaying spoilage. Another notable advantage of the-prepared packaging material lies in its completely biodegradability, therefore meeting the requirement of environmental protection. Therefore, the prepared CS-AN-CNCs film as an intelligent packaging solution with potential applications in food preservation and freshness monitoring applications.

Characteristics of bioplastics prepared from cassava starch reinforced with banana bunch cellulose at various concentrations

Human activities have led to the pollution of the environment through the accumulation of plastic waste. Since plastics are resistant to decomposition resulting negative impact on the environment, there is a pressing need for the development of bioplastics. Starch is a such of natural material that can be used made of bioplastics. However, bioplastics from starch were needed to improve starch-based bioplastics due to their brittle properties. To address this issue, researchers focused on enhancing starch-based bioplastics by incorporating cellulose, particularly derived from kepok banana bunch fibers and cassava starch variety UJ3. The production process involved adding varying concentrations of 2.5, 5, 7.5, and 10 % (wt) of kepok banana bunch cellulose. The findings indicated that increasing cellulose concentration improved the characteristics of the bioplastic materials significantly. The results showed that the addition of cellulose concentration improved the mechanical properties, water vapor absorption, and biodegradability of bioplastics. With an optimal cellulose concentration level at 7.5%, remarkable enhancements in tensile strength (from 2.92 to 6.72 MPa), reduced elongation percentage (from 20.89 to 4.06%), increased Young’s Modulus values (from 13.98 to 172.52 MPa), decreased water vapor absorption rate (from 15,93 to 11,48%), and enhanced bio-degradability rating (from 29,81 to 50,69%) were observed.

Revolutionizing protective materials: Ultrahigh peak viscosity through MOF-enhanced shear thickening fluid for advanced soft body armor

The incorporation of shear thickening fluid (STF) into aramid fabric has emerged as a compelling strategy to augment the protective attributes of aramid-based soft body armor. The peak viscosity of STF assumes a pivotal role in shaping the efficacy of this enhancement. In this study, we present an innovation in the design and synthesis of an ultrahigh peak viscosity STF using metal-organic framework (MOF)/SiO2 nanoparticles as the core constituents. The remarkable enhancement in peak viscosity of MOFs/SiO2-based STF, taking ZIF-8 as an exemplary MOFs material, is attributed to the pronounced interparticle contact friction facilitated by the rugged surface morphology of the ZIF-8/SiO2 nanoparticles. Therefore, ZIF-8/SiO2-based STF (62.5 wt.%) demonstrates a peak viscosity approximately 3938 times greater than that of conventional SiO2-based STF (62.5 wt.%). This extraordinary STF formulation has been successfully employed in aramid fabric-based soft body armor, resulting in a significantly advancement in protective performance. Compared to Kevlar fabric impregnated with SiO2-based STF (62.5 wt.%), the utilization of ZIF-8/SiO2-based STF (62.5 wt.%) results in substantial and scientifically significant improvements in key mechanical parameters. These include a notable 15.4 % increase in maximum stabbing force, a remarkable 29.5 % augmentation in maximum yarn pull-out force, a 24.3 % boost in maximum yarn tensile strength, and a 204.5 % enhancement in maximum fabric tensile strength. This research underscores the profound impact of synergizing ZIF-8 and SiO2 within the STF matrix, and significantly improves the protective abilities of SiO2-based STF-impregnated Kevlar fabrics, which provides a new route to design STF-impregnated ballistic fabric with high protective performance.

Amplifying Nanoparticle Reinforcement through Low Volume Topologically Controlled Chemical Coupling.

We present a streamlined method to covalently bond hydroxylated carbon nanotubes (CNOH) within a polyphenol matrix, all achieved through a direct, solvent-free process. Employing an extremely small concentration of CNOH (0.01% w/w) along with topologically contrasting linkers led to a maximum of 5-fold increase in modulus and a 25% enhancement in tensile strength compared to the unaltered matrix, an order of magnitude greater reinforcement (w/w) compared to state-of-the-art melt-processed nanocomposites. Through dynamic mechanical analysis, low field solid-state nuclear magnetic resonance spectroscopy, and molecular dynamics simulations, we uncovered the profound influence of linker's conformational degrees of freedom on the segmental dynamics and therefore the material's properties.

Mechanical upcycling of single-use face mask waste into high-performance composites: An ecofriendly approach with cost-benefit analysis

The COVID-19 pandemic created an unprecedented demand for PPE, with single-use face masks emerging as a critical tool in containing virus transmission. However, the extensive use and improper disposal of these single-use face masks, predominantly composed of non-biodegradable plastics, has exacerbated environmental challenges. This research presents an innovative method for mechanically upcycling PPEs used in medical sectors i.e. single use face masks. The study investigates a facile approach for reclamation of infection-free and pure polypropylene (PP) plastic from discarded single use face masks (W-PP) and blends it with various vegetable oil percentages (5, 10 and 20 %), resulting in a versatile material suitable for various applications. Melt flow index, rheological behaviour, DSC and FTIR were employed to investigate the effect of vegetable oil/radical initiator through chemical grafting on W-PP properties. The results demonstrate significant enhancements in the tensile strength and modulus of W-PP when blended with vegetable oil and a radical initiator. There was a marked increase in tensile strength (33 %) and strain (55 %) compared to untreated W-PP, rendering W-PP both robust and flexible. Furthermore, we employed this upcycled W-PP in the fabrication of glass fibre-reinforced composites, resulting in notable enhancements in both tensile strength and impact resistance. The upcycled W-PP demonstrates excellent potential for various applications, such as sheet forming and 3D printing, where the non-brittleness of plastics plays a pivotal role in manufacturing high-quality products. The cost-benefit analysis of this approach underscores the potential of upcycling PPE waste as a sustainable solution to mitigate plastic pollution and conserve valuable resources. The applications of this upcycled material span a wide range of industries, including automotive composites, packaging, and 3D printing.

Grey-Taguchi Approach for Optimizing FSW Parameters in Joining AA6262 and AA5083 Alloys

T his study concentrates on the friction stir welding (FSW) joining of dissimilar AA6262 and AA5083 plates. Four input parameters, namely tool rotational speed (TRS), welding speed (WSP), tool tilt angle (TTA), and pin depth (PDP) are chosen to analyze the output responses of tensile strength (UTS), hardness (HBN), and wear rate (WTR) in welding. The primary objective is to optimize the variables of the FSW process for AA6262 and AA5083 alloys using a combination of Taguchi and Grey Relational Analysis (GRA) methods, while also comprehending the correlations among process variables through the application of these two methods. Utilizing the Taguchi approach, L27 orthogonal array is constructed for conducting FSW experiments. After this, the multi-objective optimization challenge is streamlined into a single-objective optimization task by leveraging the grey relational degree. The significance and impact of the distinct variables are elucidated through the application of Analysis of Variance (ANOVA). Confirmation tests and predictive analysis are performed to validate the optimal variables, which are then compared against the acquired outcomes. The results highlight the welding speed as the paramount parameter, exerting substantial influence over the output responses of the welds in contrast to the other variables under examination. The application of the Grey-Taguchi methodology yields enhancements in Tensile Strength (245.23 MPa) and Hardness (99.2 Hv), while concurrently decreasing the Wear Rate (0.00456 m3/Nm). Furthermore, the Grey Relational Grade exhibits an advancement of 0.1312. These findings collectively signify an increased operational efficiency in the welding process, particularly for dissimilar alloys.